1. Field of the Invention
Apparatuses consistent with the present invention relate to an illumination device which can be miniaturized by providing uniform light with a relatively short light pipe, and a projection display including the same.
2. Description of the Related Art
In general, projection displays provide images by projecting the images produced from display devices on a screen using illumination devices. Display devices include digital micro-mirror devices (DMDs), transmissive liquid crystal display devices (LCDs), liquid crystal on silicon (LCOS), and so forth.
Illumination devices, which enable light incident from a light source to be illuminated with a uniform profile, are widely used for projection displays such as projectors and so on.
FIG. 1 is a schematic view illustrating an optical arrangement of a related art illumination device. Referring to FIG. 1, the related art illumination device includes a condenser lens 14 which condenses light incident from a light source, a light pipe 22 which mixes the light, and an illumination lens 56. The related art illumination device mixes the light incident from the light source using the light pipe 22 and thus provides uniform light. The uniform light formed at an output end of the light pipe 22 is projected onto an image display device 52 through the illumination lens 56. However, in the related art illumination device illustrated in FIG. 1, the light pipe 22 must have a predetermined length for providing the uniform light and a large space is required for arranging optical components, which makes it difficult to miniaturize the projection display. Furthermore, it is difficult to form uniform light when a plurality of light sources are used, each of which projects collimated light such as a laser beam.